Children reported a rise in online blackmail attempts involving sexual images in the UK last year, according to a leading charity.

The NSPCC said contacts with its Childline service relating to online sexual abuse and exploitation rose by 36% last year, driven by an increase in cases related to online blackmail.

Evidence of the rise in online blackmail came as MPs said that maintaining the status quo in social media regulation was “not acceptable”, before the closing date for submissions to a government consultation on online safety.

The child protection charity said the most common examples of blackmail were: financial “sextortion”, where victims are tricked into sending explicit selfies and are then sent demands for money in exchange for not releasing the images; being threatened with images taken from children’s phones and turned into explicit images using AI; and being forced to send fresh explicit images by a former partner.

Blackmail threats were discussed in two out of five online abuse-related counselling sessions at Childline last year, where children contact the service to report abuse and receive advice from professionally trained advisers. There were 2,444 sessions related to online sexual abuse and exploitation in the year to 31 March, with blackmail being mentioned in 1,043 of them.

Children contacted by the NSPCC over the past year have described being tricked into sending nude selfies by a criminal pretending to be a teenage girl, or sending photos to an older man and then being threatened about making an explicit video.

The NSPCC published the data after child safety experts recommended that schools remove pictures of pupils’ faces from their websites and social media accounts because blackmailers are using them to create sexually explicit images by manipulating the photos with AI tools.

Chris Sherwood, the NSPCC’s chief executive, said it was “crucial” the government used the safety consultation as a springboard to force tech platforms to “make these spaces safe for young users”. The consultation, which closes on 26 May, is considering an Australian-style under-16 age limit for accessing social media as well as a range of restrictions on livestreaming or addictive app features such as infinite scrolling.

The NSPCC has warned that an under-16 ban could have “unintended consequences” – such as exposing children to dangerous platforms when they turn 16 – and is calling on ministers to strengthen the online safety act [OSA], which requires tech companies to protect children from harmful content. The charity wants addictive app features to be tackled, strict age-ratings for each social media platform and smartphones to carry software that blocks nude images.

MPs on the science, innovation and technology committee have told the government that further protections on social media are needed. In a letter to the tech secretary, Liz Kendall, the committee chair, Labour MP Chi Onwurah, said the committee was “struck by the examples of a range of significant harms to individuals from the use of social media”. Onwurah called for measures including requiring tech companies to provide more data on the impact of their platforms on children and greater transparency on the algorithms that curate children’s social media feeds.

The government has already committed to some form of action, having committed last month to either repeating the Australian ban or imposing restrictions on platforms.

Responding to the NSPCC report, a government spokesperson said the OSA already protected children from online harms such as bullying and that it was working with tech companies to prevent under-18s from sharing or taking nude images.

“We won’t hesitate to go further in ensuring children are safe online, which is why we are consulting on everything, from age limits and apps curfews to an outright ban,” said the spokesperson.